Stemple Takedown Gun (STG) U9 Slow Fire (SF) - Adjustable Bolt System

2022 Update: For 2022 we are introducing the new Internally Threaded Pattern (ITP) assemblies of the Stemple 76/45 receivers to offer a more streamlined and versatile system with enhanced compatibility among setups. Per this previously approved method of attaching the trunion, separate trunions and bolt guides are no longer necessary for converting between the standard and heavy bolt systems. While these can still be used on the receiver, one trunion now does it all. For example, the previous U9 conversion to the U9 slow fire setup required separate trunions/bolt guides, bolts, stocks, and buffers. In the ITP setup only the stock and buffer assemblies are switched to add mass to the moving parts for lower cycle rates. The bolt and trunion are unchanged. The fire controls, stocks, and mag housings are also unchanged.

The conversion from the U9SF to the U45 in the combination guns is also further simplified by having a much heavier 45 bolt so a second bolt extension is no longer necessary to reduce the cycle rate.

The STG1928 parts are also fully compatible with this setup.

2023 Update: We've recently switched to NiB Battleworn™ plating (dark gray color) on the lower assembly, magazine housing, and barrel jacket. This high performance finish adds greater durability and ease of cleaning compared to the black anodized finish.

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U9 Slow Fire (SF) - Adjustable Bolt System

The Slow Fire (SF) utilizes an ultra-smooth adjustable-weight bolt system with hydraulic buffering to dissipate the energy in the recoiling mass during the cycle process. This is an ideal system for shooters looking to maximize suppressor performance by increasing dwell time in the chamber thereby reducing port noise. The cyclic rates with this system are adjustable between 525 to 900 round per minute. Shooters can customize their preferred rates simply by adjusting the bolt parts. At the lowest rate, this gun has a sustained fire of approximately 9 seconds with a 70-rd drum. The Low-Recoil Bolt System is also used for the 45ACP and 7.62x25. These setups utilize AR pattern stocks, AR pattern grips, and multiple Picatinny mount options for maximum versatility.

This gun is also ideal for use with a suppressor. The extra bolt weight drastically slows the initial bolt blow-back thereby significantly reducing port noise common in open-bolt blow-back SMGs.

Transferable

In 2003, the original inventor, John Stemple collaborated with BRP Corp to make new and replacement parts for the Stemple 76/45 receivers he manufactured prior to the 1986 cutoff. From this came a series of compatible drop-on parts for the unmodified/transferable Stemple 76/45 receivers known as Stemple Takedown Gun (STG) setups. Since nothing is welded or hand fitted to these receivers, changing setups and replacing parts is fast and easy. These are the most finely built and smooth running sub-machine guns on the transferable market. We build them for performance and durability, stock plenty of high-quality spare parts, and provide excellent service.